A concentric pneumatic clutch release bearing is a mechanical device used in friction clutches.

Its spring engages the contact surface of the outer bearing ring and applies a force induced by the pneumatic pressure and tension spring .

The actuation force forces the clutch release bearing | Pneumatic Release Bearing to release the friction clutch. In turn, the friction clutch is free to move. This article covers the design and installation of a concentric pneumatic clutch release bearing.

Concentric slave cylinders provide friction clutch release bearings

The internal slave cylinder has a bearing surface that maintains contact with the pressure plate. The slave cylinder is self-adjusting and has a spring between its base and outer surface.Pneumatic Release Bearing

The spring maintains the dimensional distance required for the clutch finger to travel. The cylinder is not constantly spinning, which prevents it from overheating and breaking.

It also allows for clutch wear. Concentric slave cylinders | Pneumatic Release Bearing are generally easier to install and maintain than other styles.

Concentric slave cylinders are used with either a push or pull-type clutch. They are compatible with any type of actuating arrangement.

Because the slave cylinder is mounted internal to the bell housing, it provides maximum clutch release bearing protection.

A concentric slave cylinder also reduces pedal effort for the driver. It also shields the internal parts of the clutch from road debris and other weather issues.

Types of concentric slave cylinders
There are two types of concentric slave cylinders: spring loaded and bolted. Spring loaded slave cylinders return to the front plate of the transmission when the clutch finger is released.

Bolted concentric slave cylinders don’t have spring pressure. However, they do require dimensional distances to ensure proper clutch finger travel. Listed below are the two main types of concentric slave cylinders.

Design of concentric slave cylinders
The slave cylinder functions as the hydraulic actuator of a pneumatic clutch release bearing. The slave cylinder is usually composed of two main parts: a piston and an internal spring.

Both parts are protected by a rubber boot. The release bearing keeps the diaphragm spring in preloaded contact with the disk. The pushrod is normally tipped with a mushroom-shaped bushing.

This reduces surface wear on the pushrod tip and the length of the rod is critical for proper operation of the hydraulic system.

Concentric slave cylinders are known for their configuration. They typically have a central bore and are used with either a pull-type or a push-type clutch.

They can also be used with other types of actuating arrangements. The release bearing is generally mounted on a piston and brought into contact with the release lever of the associated clutch.

A concentric slave cylinder can operate in either case.

Installation of concentric pneumatic release bearing
In order to install a concentric pneumatic clutch release bearing, a shim must be used between the slave cylinder and the input bearing retainer. The shim should provide a 50/1000 air gap at the disc.

After the shim has been installed, the release bearing must be backed out by a minimum of four millimeters to ensure proper clutch finger travel. The next step is to install the bearing on the transmission.

The following installation guide will help you complete the job.

Ensure that the new clutch release bearing fits properly and correctly enables the driver to engage and disengage the clutch.

The clutch pedal assembly contains a nut that threads onto the rod. This adjustment should be done on every clutch installation.

The clutch shim should be measured from the transmission mounting face on the engine block, the bell housing flange, and the release bearing on the fully retracted slave cylinder.